In order to improve performance of wireless communication, efficient use of a radio spectrum is needed. However, intercell interference in a network environment, in which a plurality of cells is densely collected, is a significant cause of restricting the improvement of the performance. Accordingly, research has been conducted recently on cooperative transmission technology between multi-cells in order to address the intercell interference issue. There is a Coordinated Multi-Point (CoMP) transmission and reception technology introduced in the 3rd Generation Partnership Project (3 GPP) Long Term Evolution (LTE) Rel.11 standard as one of the cooperative transmission technologies between multi-cells.
In the CoMP technology, an intercell interference signal may be dynamically blanked, or an interference signal may be converted into a reception desired signal through intercell cooperation to be transmitted. Accordingly, when the CoMP technology is used, performance of a cell-edge is improved, and a cell coverage area is improved, so that spectrum efficiency may be improved.
In the meantime, in order to improve performance of the CoMP technology, much research has been recently conducted. However, in order to maximally utilize new Degrees Of Freedom (DOF) provided by the cooperation between multi-cells, a centralized scheduler, which is aware of an interference situation between CoMP cooperating cells, needs to be used.
A main role of the centralized scheduler is to select the best User Equipment (UE) for each cell and determine a spatial multiplexing ratio so that a sum of rates is maximal. In order to efficiently allocate wireless resources to UEs within a cluster formed of a plurality of cells (for example, a plurality of Transmission Points (TPs)) connected with the centralized scheduler or a plurality of Radio Remote Heads (RRHs) or macro cell enhanced Node B (eNB)s or small cell eNBs (hereinafter, referred to as “TPs”), the centralized scheduler needs to obtain Channel State Information (CSI) between all of the UEs within the cluster and the TPs. Accordingly, the centralized scheduler receives the CSI from the TPs through an interface, that is, a backhaul, for communication between the centralized scheduler and the TPs.
An Ethernet backhaul, an optical fiber backhaul, and the like, may be used as the backhaul. However transception of the CSI through the backhaul (more particularly, the Ethernet backhaul) may cause a delay. When the transception of the CSI is delayed, scheduling (i.e., allocating wireless resources and a Modulation and Coding Scheme (MCS) to UEs within a corresponding cluster) is performed based on the delayed CSI, which deteriorates performance of the CoMP. For example, a scheduling scheme using the typical centralized scheduler is considerably vulnerable to the backhaul delay, and scheduling cannot be performed based on accurate CSI in an ever-changing wireless environment.
Therefore, a need exists for a method and an apparatus for performing scheduling capable of decreasing intercell interference and improving cell throughput in a wireless communication system.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.